Retinoic acid and its natural and synthetic analogues (retinoids) exert a wide array of biological effects. ##STR2##
They have been shown to affect cellular growth and differentiation and are promising drugs for the treatment of several cancers. Roberts, A. B. and Sporn, M. B. in "The Retinoids," Sporn, M. B., Roberts, A. B., and Goodman, D. S., eds, 1984, 2 pp. 209-286, Academic Press, New York; Lippman, S. M., Kessler, J. F., and Meyskens, F. L., Cancer Treat. Rep., 1987, 71, p. 391; ibid., p. 493; Hong, W. K. et al., N. Engl. J. Med., 1990, 323, P. 795; Huang, M. et al., Blood, 1988, 72, p. 567. A few retinoids are already in clininal use in the treatment of dermatological diseases such as acne and psoriasis. For example, isotretinoin is used clinically for oral therapy of severe acne, and etretinate is particularly useful in the treatment of psoriasis. Orfanos, C. E., Ehlert, R., and Gollnick, H., Drugs, 1987, 34, pp. 459-503. ##STR3##
Other examples of retinoid compounds include arotinoid of formula II and retinobenzoic acid of formula III, in which X equals --NHCO--, --CONH--, --COCH.dbd.CH--, --CH.dbd.CHCO--, --COCH.sub.2 --, etc. ##STR4##
See for example: Loeliger, P., Bollag, W., and Mayer, H., Eur. J. Med. Chem. 1980, 15, pp 9-15; Kagechika, H. et al., J. Med. Chem., 1988, 31, No. 11, pp 2182-2192.